Sadeghpour Parisa, Haghighi Mohammad, Ebrahimi Alireza
Chemical Engineering Faculty, Sahand University of Technology, P.O.Box 51335-1996, Sahand New Town, Tabriz, Iran; Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O.Box 51335-1996, Sahand New Town, Tabriz, Iran.
Chemical Engineering Faculty, Sahand University of Technology, P.O.Box 51335-1996, Sahand New Town, Tabriz, Iran; Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O.Box 51335-1996, Sahand New Town, Tabriz, Iran.
Ultrason Sonochem. 2021 Apr;72:105416. doi: 10.1016/j.ultsonch.2020.105416. Epub 2020 Dec 7.
The influence of ultrasound-assisted rapid hydrothermal synthesis of aluminosilicate ZSM-5 catalysts was examined in this work. A series of MFI-type nanostructured materials with sonochemical approach and conventionalheating were synthesized and evaluated for conversion of methanol to propylene reaction. The prepared samples were tested by characterization analyses such as XRD, FESEM, BET-BJH, FTIR, TPD-NH and TG/DTG. The obtained results confirmed that ultrasound treatment enhanced the nucleation process and crystal growth for ZSM-5 sample synthesized at moderate temperature of 250 °C. Therefore, it was found the formation of pure MFI zeolite with high crystallinity and improved textural, structural and acidic properties for ZSM-5(UH-250) sample compared with the other zeolites. This observation was attributed to the relationship between the perfect crystallization mechanism and catalytic properties, which led to producing an efficient MFI zeolite toward the optimal catalytic performance. In this manner, the methanol conversion and products selectivity of prepared materials were carried out in MTP reaction at 460 °C and atmospheric pressure. The ZSM-5(UH-250) zeolite with slower deactivation regime exhibited the constant level of methanol conversion (84%) and high propylene selectivity (78%) after 2100 min time on stream. Moreover, the synthesis pathway for MFI zeolite at moderate temperature and also deactivation mechanism of improved sample were proposed.
本工作考察了超声辅助快速水热合成铝硅酸盐ZSM-5催化剂的影响。采用声化学方法和传统加热方式合成了一系列MFI型纳米结构材料，并对甲醇制丙烯反应的转化率进行了评价。通过XRD、FESEM、BET-BJH、FTIR、TPD-NH和TG/DTG等表征分析对制备的样品进行了测试。结果表明，超声处理促进了在250℃中温合成的ZSM-5样品的成核过程和晶体生长。因此，与其他沸石相比，发现ZSM-5(UH-250)样品形成了具有高结晶度且改善了织构、结构和酸性的纯MFI沸石。该观察结果归因于完美的结晶机制与催化性能之间的关系，这导致产生了具有最佳催化性能的高效MFI沸石。通过这种方式，在460℃和常压下的MTP反应中对制备材料的甲醇转化率和产物选择性进行了研究。具有较慢失活速率的ZSM-5(UH-250)沸石在2100分钟的反应时间后表现出恒定的甲醇转化率(84%)和高丙烯选择性(78%)。此外，还提出了中温下MFI沸石的合成途径以及改进样品的失活机理。
